I have an order down for the Amazon release and a standard release. Also, I will have no regrets. It's exactly 6 months away from release and I'm pretty sure I can put a few hundred bucks together by then...
Hasbro haven't announced if or when they will be releasing Soundwave. I'm sure they will, but it will be at least a year away. It will probably be exclusive and may not be released here. MP Rodimus was easy to find at a good price, MP Grimlock was at a decent price but I never even saw one, I'm not sure if Skywarp was even released here, MP Ghost Starscream was massively overpriced despite shelf-warming, MP Starscream was hard to find etc...
You can look at the potential $100 price difference as "impatience tax" or you can look at it as "assurance". Or both, as I do.